带有IN子句和限制的PHP PDO
我正在尝试使用PDO和LIMIT执行带有IN子句的语句 在本教程之后,我成功地构建了正常工作的代码,但并没有像它应该的那样检索数据带有IN子句和限制的PHP PDO,php,mysql,pdo,sql-limit,sql-in,Php,Mysql,Pdo,Sql Limit,Sql In,我正在尝试使用PDO和LIMIT执行带有IN子句的语句 在本教程之后,我成功地构建了正常工作的代码,但并没有像它应该的那样检索数据 $inStmt = DB::prepare("SELECT following_user_id FROM following WHERE user_id=?"); $inStmt->execute([$userId]); $arr = ($inStmt->fetchAll(PDO::FETCH_NUM));
$inStmt = DB::prepare("SELECT following_user_id FROM following WHERE user_id=?");
$inStmt->execute([$userId]);
$arr = ($inStmt->fetchAll(PDO::FETCH_NUM));
$array = array();
foreach ($arr as $element ) {
$array = array_merge($array, $element);
}
$in = str_repeat('?,', count($array)) . '?';
$params = array_merge($array,[$userId]);
$sql = "SELECT * FROM user_tweets WHERE user_id IN ($in) ORDER BY tweet_date DESC LIMIT 20 OFFSET ?";
$stmt = DB::prepare($sql);
for ($x = 0; $x <= count($params) - 1; $x++) {
$param = $params[$x];
echo " ID:" .($x+1) . " PARAM:". $param;
$stmt->bindParam(($x+1),$param);
}
$param = (int)$startFrom;
echo " ID:" .(count($params)+1) . " PARAM:". $param;
$stmt->bindParam((count($params)+1),$param,PDO::PARAM_INT);
$stmt->execute();
return $stmt->fetchAll(PDO::FETCH_ASSOC);
查询还应创建以下内容:
SELECT * FROM user_tweets WHERE user_id IN (?,?,?) ORDER BY tweet_date DESC LIMIT 20 OFFSET ?
我的代码有什么问题?我很困惑,因为一切都应该很好(当我用下面已经设置好的变量调用我的数据库时,它确实会返回几行,所以它也应该使用PDO,但不返回任何内容)
这似乎是一种更简单(且无限快)的方式来做同样的事情:
SELECT t.*
FROM following f
JOIN user_tweets t
ON t.user_id = f.following_user_id
WHERE f.user_id=?
ORDER
BY t.tweet_date DESC
为什么不直接使用连接呢?
SELECT * FROM user_tweets WHERE user_id IN (42,41,53) ORDER BY tweet_date DESC LIMIT 20 OFFSET 0
SELECT t.*
FROM following f
JOIN user_tweets t
ON t.user_id = f.following_user_id
WHERE f.user_id=?
ORDER
BY t.tweet_date DESC